In San Francisco's Outer Sunset neighborhood, the sidewalks stretch a dozen feet wide, thanks to residents who have paved over their entire front yards - and city agencies that do little to cite them, though the practice has been outlawed since 2002.

"It's illegal to pave over your yard, but it's pretty widely ignored, and people do it with impunity," said Jonathan Frank, 56, a retired teacher who has lived on 33rd Avenue for 10 years. "The two main reasons are that they want an extra parking spot, and it's a pain to take care of the garden area."

Under city law, at least 20 percent of a front yard must consist of permeable surfaces with vegetation, mostly to allow for proper drainage and to keep the neighborhood looking green. Homes can be reviewed for compliance every time an owner does construction on the driveway or property.

The Board of Supervisors passed the ordinance in 2002, but the law didn't have much bite until 2008, when lawmakers gave the city the power to fine homeowners $500 if they ignored a 90-day warning to add greenery.

But even that wasn't enough to break up the concrete - many residents thought that if they paid the fines, they could keep their front yards as is. Supervisor Carmen Chu got the penalties stiffened to $250 for each day beyond 30 days' notice.

The fines may be steep, but the Planning Department doesn't have the staffing to monitor for compliance, said spokeswoman Joanna Linsangan. Enforcement is 100 percent complaint-driven, she said.

"As it stands right now, we do have a very high backlog, and so there are a number of cases that we still have to review and complaints we have to look into," Linsangan said.

The department has received 163 complaints citywide related to paved-over front yards since 2002, 88 of which came from Chu's district. As of December, 95 targets of complaints had brought their front yards into compliance.

The Planning Department is allowed to be lenient if residents have extenuating circumstances, such as financial hardship, Chu said.

"I can tell you, just taking a look at some of my neighbors who have paved portions of their yard, a lot has to do with the fact they're getting older in age, their kids are no longer in the household, or they don't have the physical ability to maintain it," Chu said. "But the rules are there to help with the curbside appeal issues and primarily the environmental issues."

If rainwater can't flow into the ground, it drains into the sewer system. Heavy, sudden rains can overwhelm the system and lead to sewage spills, such as one near Ocean Beach in November that forced the closure of a stretch of sand for cleanup.

The concrete-coated front yards also make tempting parking spots, but it's illegal to put a car there - the planning code forbids blocking any part of the sidewalk or driveway in front of the house.

What's not working

Issue: Residents in San Francisco's Outer Sunset illegally pave over their front yards to avoid maintaining gardens and to create extra parking spaces. Enforcement is spotty, though the practice has been illegal for more than a decade.

What's been done: Since 2002, when the paving became illegal, 163 complaints have been filed with the Planning Department, and 95 of those have been resolved.

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